Problem

You want to post JSON data to a flow.

Solution

Use the HTTP In node to listen for POST requests that have their Content-Type set to application/json and access the parsed JSON as properties of msg.payload.

Example

Show flow

[~]$ curl -X POST -d '{"name":"Nick"}' -H "Content-type: application/json" http://localhost:1880/hello-form
<html>
    <head></head>
    <body>
        <h1>Hello Nick!</h1>
    </body>
</html>

Discussion

When the HTTP In node receives a request with the Content-Type header set to application/json it parses the body of the request and makes the data available under msg.payload:

var name = msg.payload.name;